Stream_support: Add testcase for read_VTK.

[afabri]

Summary of Changes

Did only compile when the PolygonRange was a std::vector<std::vector<std::size_t>> . Now it supports any RandomAccessContainer instead of std::vector. The documentation states that it may be a SequenceContainer, but that is not implemented. For example it does not compile for std::list<Face>.

Todo

• [ ] Discuss if we want to change the documentation or the code. Note that most PMP algorithms accept only models of RandomAccessContainer.

Release Management

• Affected package(s): Stream_support
• License and copyright ownership: unchanged